Carburetor



CARBURETOR Filed Dec. 6, 1955 2 sbaglia-'sheet 2 W @@MCM ATTORNEY Patented May 25., 1.937'

UNITED STATES PATENT OFFICE v CARBURETOR of Switzerland Application December 6, 1935, Serial No. 53,188 l In France December 6, 1934 9 Claims.

L'The' present invention relates Ato carburetors wherein the fuel spray outlet is fed from the fuel chamber of a pressure regulator comprising a diaphragmwhich closes said chamber and actuates a valve controlling the admission of fuel to s'aid chamber.

One object of the invention is to create in the fuel, at the level of the fuel outlet, a pressure which is independent of the inclinations of the carburetor in any direction.

The invention is particularly concerned with carburetors adapted to acrobatic iiying.

One object of the invention is to provide a carburetor comprising aweighted lever adapted to pivot around an axis and connected at one end to the diaphragm of the pressure regulator, preferably at the centre thereof. The distribution of the weight of the lever and the relative position of the lever axis and of the spray outlet are such that a straight line connecting the spray outlet to the centre of the diaphragm is perpendicular to the plane dened by the lever axis and the centre of gravity thereof.

Further objects and advantages will be apparent to those skilled in this art from the" following description taken in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal section of a carburetor embodying the invention. Figure 2 illustrates a geometrical diagram showing the effectiveness ofthe invention? Figure 3 is a diagrammatic longitudinal section of another embodiment of the invention. l

Referring to Figure l, there is shown a carburetor in which the mixing chamber l is fed with fuel through an outlet 2 receiving liquid fuel (not atomlzed)`; By spray orifice is meant the point where the fuel, previously in liquid state, is spread in a gaseous atmosphere. The fuel outlet 2 is fed with fuel by a pressure regulator comprising a iiexible diaphragm 4. The fuel chamber 3 communicates, through an orifice 6 controlled by a' valve 1 connected to the diaphragm 4, with a conduit containing fuel under pressure.

A lever pivoting around an axis 9 engages a bracket Il fixed to the diaphragm 3. A designates the spray orifice; C the centre of the diaphragm; L the geometrical axis on which lever s 8 is pivotally mounted; G the centre of gravity of the lever andV D the base of the perpendicular dropped from lGto the shaft L. y

If the diaphragm is perfectly iiexlble, that is to say if it does not oppose any resistance to deformations, the diaphragm 4 and the valve 1 assume a position of equilibrium during operation.' For said position, the pressure exerted by the fuel on .the face of diaphragm 4 in contact with the fuel, equilibrates the atmospheric pres-V sure exerted on theopposite side of the vdiaphragm plusvthe pressure exerted by weighted 1ever`8 on said diaphragm.

In the absence of lever 8, the fuel pressure on the diaphragm 4 would only have to balance the atmospheric pressure, so that the pressure on the fuel at the centre C of the diaphragm, would be equal to the atmospheric pressure, while the pressure on the fuel at the level of the spray oriiice A would be weaker than the atmospheric pressure, the dierence between the atmospheric pressure and the pressure at .this level being measured by a liquid height equal to 'the vertical distance between C and A.

If the pressure on the fuel at the level of the spray orifice A is equal to the atmospheric pressure, the liquid column comprised between this spray orifice and the diaphragm exerts on said diaphragm a certain pressure which is to i be added to the atmospheric pressure. In order that the pressure at the level of the spray orifice A be equal to the atmospheric pressure, it is thus necessary that lever 8 exert on the diaphragm 4 a pressure which equilibrates the'pressure exerted by the liquid column on the diaphragm 4.

The thrust F exerted by the diaphragm 4 on the end l0 of lever 8, under the action of the liquid column, is perpendicular to the diaphragm and proportional to the vertical distance between the spray orifice A and the centre C of the diaphragm. The thrust exerted by the end I0 oi lever 8 of the diaphragm by the weight P of the lever is proportional tothe moment of said weight abolt the axis L. Referring to Figure 2, where only the axis L, the centre of gravity G of lever 8, the centre C oi' the diaphragm and the spray orifice A are illustrated for a given inclined position of the apparatus, the moment of weight P with respect to axis Ly is equal to GP'XOG, wherein GP' designates the projection of the weight P on a perpendicular to the plane dened by the axis L and centre of gravity G.

The vertical distance between the spray oriiice A and centre C of the diaphragm is represented by the projection AA" of straight line AC on the vertical.

According to the invention, straight line CA is perpendicular to plane (L, G) and consequently is parallelto straight line GP. Ii.' p is the angle of the two parallel straight lines GP' and AC with the vertical, the .moment of. weight P about the axis L is equal to GPXOGXcos p while the vertical distance AA' is equal to ACXcos p.

It can thus be seen that the moment of weight P relatively to the axis L and the vertical distance between the spray orifice A and the centre of the diaphragm are both proportional to cos go and are therefore in a constant ratio whatever be the inclinations of the apparatus. The same is true of the stress exerted by the lever end I on the diaphragm 4 under the action of weight P and of the thrust F transmitted by the diaphragm 4 to the end Ill under the action of the liquid column. Itis therefore merely necessary to choose a proper value for weight P in order that .these stresses and thrust be equal for any position of the apparatus and, consequently, in order that the pressure in the fuel at the level of the spray orii'ice A be equal to the atmospheric pressure, whatever be the position of the ap-f paratus.

In practice, the value which must be given to weight P, in order that this weight equilibrates the liquid column for a given particular position of the carburetor, would be determined by experiment. The realization of the geometrical condition, according to which the -straight line CA connecting the centre of the diaphragm to the spraying outlet is perpendicular to the plane determined by the centre of gravity G of the lever and the axis L of this lever, of course necessitates the determination of the centre of gravity G either by experiment or by calculation.

If the spray orice is located exactly at the levelI where the fuel pressure is equal to the atmospheric pressure, it may occur that fuel will flow by .capillary action when the engine fed by the carburetor stops. According to the invention, in order to obviate this inconvenience, the spray orifice is located slightly above this level when the carburetor is in the normal position, the distance being sufficiently short that the pressure at the level of the spray orifice is substantially independent of the inclinations of the apparatus.

In Figure 1, the spray orifice A is shown opening into the mixing chamber of the carburetor. It is obvious that all that has been said concerning: Figure 1 would be applicable in case of the discharge orifice A opening into an intermediate atomizing chamber as it is immaterial, so far as the invention is concerned, whether the fuel be mixed to all or to only a portion of the air when issuing from the spray orifice. In all cases, the liquid column which has to be considered terminates at the point where the liquid fuel meets the air and mixes therewith. It is this point which has been designated by spray orifice.

Moreover, it has been assumed that the side of the diaphragm 4 which is not in contact with the fuel is submitted to the atmospheric pressure. This was but an example and it is obvious that the pressure supported by this side of' in contactwith it, but Valso by a spring. This is Walling in the fuel at the level of the spray orifice due to the fact that the pressure exerted by a spring on the diaphragm is independent of the position of the apparatus, so that if the dia.-

phragm is-loaded by a spring, the pressure pre- In Figure 3 there is shown a carburetor embodying the invention and in which the fuel chamber 3 feeds a spray'orice'A opening linto the atomizing chamber I3. The atomizing chamber I3 is fed with air by an orifice I4 and the atomized fuel is delivered into the mixing charn- According to the invention, the straight line' CA connecting the center of the'` diaphragm to the spray orifice is perpendicular to the plane defined by the axis L and the centre of gravity G of lever 8. Under these conditions, the pressure of the fuel at the level of the spray orifice A is independent of the inclination of lthe apparatus.

Although the point of connection of the diaphragm to the lever is preferably arranged Aat the center of the diaphragm, this condition is not obligatory, since the connection may be located at a point other than the centre, but obviously should not be too near the edges of the diaphragm.

What we claim is:

-1. In a carburetor, a fuel outlet, a pressure regulator supplying fuel to said outlet and comprising a fuel chamber closed by a. diaphragm controlling admission of fuel to said chamber, a Weighted lever adapted to pivot around an axis and to be connected at 'one end to the centre of said diaphragm for balancing the pressure exerted by the column of fuel between the fuel outlet and the center of the diaphragm, the distribution of the weight of said lever and the relative positions of the lever axis and of the fuell outlet being such that a straight line connecting the fuel outlet to the centre of said diaphragm is perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

2. In a carburetor, a fuel outlet, a pressure regulator supplying fuel to said outlet and comprising .a fuel chamber closed by a diaphragm, a valve actuated by said diaphragm for controlling the admission of fuel to said fuel chamber, a weighted lever pivoting around an axis and connected to the centre of the diaphragm, for balancing the pressure exerted by the column of fuel comprised between the fuel outlet and the centre of the diaphragm, a straight line connecting the centre of.

the diaphragm to the fuel outlet being perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

3. In 'acarbureton a mixing chamber, a fuel outlet in this mixing chamber, a pressure regu-` lator supplying fuel to said outlet and comprising a fuel chamber closed by a diaphragm controlling admission of fuel to said chamber, a weighted leveradapted to pivot around an axis and to be connected at one end to, the centre of said diaphragm for balancing the Hpressure exerted by the column of fuel between the fuel outlet and the centre of the diaphragm, the distribution of the weight of said lever and the relative positions of the lever axis and of the fuel `outlet being such that a straight line connecting the fuel outlet to the centre of said diaphragm is perpendicular to the plane defined by the lever`V axis and the centre of gravity of said lever.

4. lIn a carburetor, a mixing chamber, a fuel outlet in this mixing chamber, a pressure regu-r lator supplying fuel to said outlet and comprising a fuel chamber closedby a diaphragm, a valve actuated by said diaphragm for controlling the admission of fuel to said fuel chamber, a weighted lever pivoting around an axis and connected to the centre of the diaphragm, for balancing the pressure exerted by the column of fuel comprised between the fuel outlet and the centre of the diaphragm, a straight line connecting the centre of the diaphragm to the fuel outlet being perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

5. In a carburetor, a mixing chamber, an atomizing chamber communicating withv the mixing chamber, a fuel outlet in said atomizing chamber, a pressure regulator supplying fuel to said outlet and comprising a fuel chamber closed by a diaphragm controlling the admission of fuel to said fuel chamber, a weighted lever pivoting around an axis and connected to the diaphragm adjacent the centre thereof for balancing the pressure exerted on said diaphragm by the fuel column comprised between the fuel outlet and the centre of the diaphragm, a straight line connecting the fuel outlet to the centre of the diaphragm being perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

6. In a carburetor, a mixing chamber, a fuel outlet in this mixing chamber, a pressure regulator supplying fuel to said outlet and comprising a fuel chamber closed by a spring loaded diaphragm controlling admission of fuel to said fuel chamber, a weighted lever, adapted to pivot around an axis and to` be connected at one end to the centr of said diaphragm for balancing the pressure exerted by the column of fuel between the fuel outlet and the centre of the diaphragm,

the distribution of the weight of said lever and the relative positions of the lever axis and of the fuel outlet being such that a stralght'lne connecting the fuel outlet to the centre of said diaphragm is perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

7. In a carburetor, a mixing chamber, an atomizing chamber communicating with the mixing chamber, a fuel outlet in said atomizing chamber, a pressure regulator supplying fuel to said outlet and comprising a fuel chamber closed by a spring loaded diaphragm controlling the admission of fuel to said fuel chamber, a weighted lever pivoting around an axis and connected to the diaphragm adjacent the centre thereof for balancing the pressure exerted on said diaphragm by the fuel column comprised between the fuel outlet and the centre of the'diaphragm, a straight line connecting the fuel outlet to vthe centre of the diaphragm being perpendicular to the plane defined by the lever axis and the centre of gravity of said lever.

l8. In a carburetor, a mixing chamber, a fuel nozzle positioned to discharge into the mixing chamber, and a pressure regulator supplying fuel to said nozzle and comprising a fuel chamber having a movable wall, a valve connected to said wall and controlling the inflow of fuel to said-fuel chamber, a lever pivotally mounted on the carburetor and connected at one end to said wall for balancing the pressure exerted by the column of fuel between the nozzle outlet and the wall, the distribution of the weight of said lever relative to its pivot and to the nozzle outlet being such that a straight line connecting the latter to the center of pressure of said wall 'is perpendicular to the plane defined by the pivot and the center of gravity of said lever.

'9. 'Ihe invention dened in claim 8, wherein a spring yieldngly urges the valve toward its operi position.

PAUL XAVIER AUGUSTE GISTUCCI. JOHANN ,LICHTENSI'EIN 

